Reflective means used in connection with fluorescent tubes or lamps

ABSTRACT

A reflector for a fluorescent tubular light. The reflector is formed by an elongated shell of parabolic cross section. A smaller but also parabolic rib extends lengthwise along the apex of the shell parabola.

United States Patent 1191 DeLlano Aug. 13, 1974 REFLECTIVE MEANS USED IN 3,152,765 10/1964 Wohlers 240/41.35 R

CONNECTION WITH FLUORESCENT 3,233,096 2/l96 6 Schmrtt TUBES OR LAMPS 3,363,093 1/1968 Schmrtt 240/103 R [76] Inventor: Mary Duarte DeLlano, Apartado Aefeo, Medellin, Colombia 52032 Primary Examiner-Richard L. Moses F1 N 7 Attorney, Agent, or Firm-Ladas, Parry, Von Gehr, [22] 1.972 Goldsmith & Deschamps [21] App]. No.: 304,455

[52] US. Cl.240/5l.11 R, 240/41.35 R, 240/103 R,

240/ 103 B [57.] ABSTRACT [51] Int. Cl. H05b 33/02 [58] Field of Search 240/5l.1 1 R, 41.35 R, 103 R, A reflector for a fluorescent tubular light. The reflec- 240/1 1.4 R, 103 B tor is formed by an elongated shell of parabolic cross section. A smaller but also parabolic rib extends [56] References Cited lengthwise along the apex of the shell parabola.

UNITED STATES PATENTS 2,262,157 11/1941 Bealsn 240/51.11 R 3 Claims, 5 Drawing Figures PATENIEU Mir; 1 31924 smnznr pmmgmum 31914 3, 829.677

slmsur FIG. 5

REFLECTIVE MEANS USED IN CONNECTION WITH FLUORESCENT TUBES OR LAMPS This invention concerns generally the field of illumination and specifically reflective means used in connection with fluorescent tubes or lamps.

Until now, in this field, reflectors have been used in various geometric forms in order to increase reflective efficiency. One type of general use has comprised a reflector formed by angular planes, for example, in the manner of a truncated pyramid incorporating rectangular planes with acute angles disposed in variousdegrees. The use of such reflectors produces a low reflection yield since light falling on the upper plane of the reflector is reflected back on to the light source, thereby reducing the illuminating power of the lamp. Similarly, tube lights using reflectors having a part circular section suffer from the same disadvantages as the aforementioned angular reflectors.

This invention has as its main object to provide an improved reflector which overcomes the aforementioned disadvantages and provides a significant advance in the techniques of illumination. It has been established that a reflector with a cross section in the form of a parabola or the like provides the greatest degree of useful reflection.

For a still further increase in light reflection, the invention utilizes the provision of a ribthroughout the length of the parabolic vertex of the reflector. The rib is similarly parabolic in cross section with its vertex pointing inwards or outwards of the body of the reflector. The length of the axis of the parabola of the aforementioned rib is variable, but obviously always substantially less than the axis of the parabola of the reflector. The form of reflector described, is supplemented at its extremes in an octahedric or ovoid shape with appropriate heights in order to improve reflection at the ends of the reflector.

In operation, a fluorescent tubular light is placed with its axis disposed over the geometric focus of the reflector. With this arrangement the reflector, not having rectangles or acute angles, even at its upper part, is able to utilize rays of light which are usually largely wasted because of rebound.

The invention will be understood still further from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of a reflector of the invention together with conventional accessory parts.

FIG. 2 is a plan view of the reflector of FIG. 1;

FIG. 3 is an elevation view of the reflector of FIG. 1;

FIG. 4 is a cross section of the reflector of FIG. 1; and

FIG. 5 is a schematic view of the reflector and parabolic reflection.

Referring to the drawings, numeral 10 indicates the reflector which, as can be seen more clearly in FIG. 5, embodies a shell of parabolic cross section and a rib 14. In this particular embodiment the vertex of the. rib points towards the inside of the reflector. In an alternative arrangement, the rib 14 may also have its vertex pointing outwardly of the reflector. Also, the geometry of the parabola may vary. The parabolic form shown in FIG. 5 is one of perfect luminous possibilities that determine the specialty, or type, of reflector to be made.

The illustrated reflector is, in fact, one of approximately 31 patterns.

A conventional fluorescenttubular light, shown generally at A, has its axisdisposed over the geometric focus F of the reflector 10.

Referring again to FIG. 5, the group of vertical parallel arrows indicate the predominant paths of reflected light andthe arrows at the upper part of the Figure show the paths of reflected rays which are deflected so as not to strike the surface of the tube A. In this manner the amount of light available for illumination is enhanced. The generally parabolic shape of the reflector 10 is modified by the rib 14 which is also parabolic. Light rays encountering the parabolic rib are reflected and are not impeded by tube A. The presence of the rib 14, disposed in any one of the aforementioned ways, is thus a determinant factor for the high efficiency of the reflector of the invention.

FIG. 4 shows a modification of the invention where the reflector serves two fluorescent tubular lights A. It will be understood, naturally, that the reflector of the invention may be used with the above mentioned high illuminating efficiency, for a variable number of tubular lights. Moreover, it will be seen that it can be also used in the construction of a modular reflector, i.e., several reflectors may be disposed in side relationship with each other, in which case mechanical means will be used for their conventional attachment.

The reflector may be made of sheet metal by means of any mechanical process. It may also be made in a plastic material including acrylic, of which Plexiglas is representative. The latter acrylic plastic material, which is commercially available and marketed by Rohm & Haas Co., results in a specially appropriate material for its construction, due to its molding qualities, mechanical strength, its significant degrading re sistance to heat and light, and its high resistance to chemical attack. If the material used is transparent to light it can be rendered opaque in any appropriate manner. For example, in the case of a material having the optical characteristics of glass, the surface should be highly polished in order to achieve maximum reflectivity.

As already mentioned, the reflector may be a unit by itself or may be formed by a series of units molded or attached in side-by-side relationship. Referring to FIG. 5, there is shown, schematically, a tubular light A with its longitudinal axis located over the focus of the reflector 10 of parabolic cross section. The section is modified at its vertex by a rib 14 also of parabolic cross section, with its axis coaxial with the parabola forming the cross-section of said reflector 10. The group of parallel arrows shown at the left of FIG. 5 indicate the predominant path of luminous reflection whereas the arrows at the upper part of the Figure show the path followed by luminous rays produced by the upper part of the tubular light. It will be seen that in its path a luminous ray strikes either against the parabolic wall of the rib 14 and when reflected thereby avoids the tube A, or else against the wall of reflector l0 and again avoids rebound against the tubular light. Consequently, all light produced by the upper half of tube A is efficiently reflected to avoid the tube and thereby prevent loss of illumination.

Referring to FIG. 1, a reflector 10 is shown for use with two tubular lamps. As described, the reflector is parabolic in section with a parabolic rib 14 (FIG. 4)

pointing, in this embodiment, towards the inside. As hereinbefore mentioned, the parabolic rib may point outwards and still achieve the same luminous efficiency. The reflector is mounted on a support structure including end members 11 for support of sockets 17. The end members 11 are centrally joined on the upper side by means of a bridge 12 which can serve as a support for ballast 16 if so required by the type of installatlon.

The extremities of the walls of the reflector are provided with flanges extending laterally outwards. Similarly, out turned flanges are provided on the end members 1] and the reflector and end members are joined together by bolts 18 extending through the superimposed flanges and secured by nuts.

Additionally, the end members are provided with grooves 13 mating with the sockets 17 which are fixed thereto by means of bolt and nut assemblies 19.

A mask 20 may optionally be fixed to the inside face. Such mask may be for decorative purposes and may conveniently be colored for indicative purposes.

Referring again to FIG. 1, elongated grooves are provided for air passage.

Referring to FIG. 2, which shows a plan view from the lower side, the reflector is shown to be in the form of an octahedron or ovoid with an aperture 21 (FIGS. 2 and 4) in the end thereof.

The foregoing is the description of what is considered the best practical embodiment of the invention. Nevertheless, it will be understood that various modifications can be introduced without departing from the essence of the invention. Similarly, it will be understood that the reflector, with appropriate mounting equipment, may be built-in or super-imposed on false ceilings or conventional finishes.

What I claim is:

1. A reflector for a fluorescent tubular light, said reflector incorporating an elongated shell of parabolic cross section with a rib integral with and extending lengthwise along the shell at the apex of the parabola, said rib being also parabolic in cross section with the major axis thereof parallel to the major axis of the shell.

thereof parallel to the major axis of the shell. 

1. A reflector for a fluorescent tubular light, said reflector incorporating an elongated shell of parabolic cross section with a rib integral with and extending lengthwise along the shell at the apex of the parabola, said rib being also parabolic in cross section with the major axis thereof parallel to the major axis of the shell.
 2. A reflector as claimed in claim 1, wherein the parabolic rib is directed inwardly from the shell apex.
 3. A reflector for fluorescent tubular lights comprising at least two elongated shells lying side-by-side and interconnected, each said shell being of parabolic cross section with a rib integral with and extending lengthwise along the shell at the apex of the parabola, said rib being also parabolic in cross section with the major axis thereof parallel to the major axis of the shell. 